SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b209e4942272cc5eed129636ebc4dcf1cfb7d2918a1d110f398a14657bc4df0a' 
  AND token = 'VfSjmkyqWGZR5urPxIHiHSWaoU4goDh+a/xJkm55E+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}